Numerous attempts have been made to adapt certain optical characteristics of ophthalmic lenses, or spectacles eyeglasses, dynamically in order to improve comfort or in order to provide new functions for wearers of the lenses. By way of example, the light transmission of lenses can be reduced under conditions of high brightness, and can be increased again when ambient light returns to a normal or low level of intensity. Photochromic lenses perform this function, but the variations in light transmission provided by such lenses are determined by the intensity of ultraviolet radiation illuminating the lenses. The light transmission level adopted by photochromic lenses is therefore unsuitable under certain circumstances. In particular, photochromic lenses inside a car remain in a state of high transparency whenever the level of sunlight. A car driver is therefore not protected against being dazzled when wearing spectacles with photochromic lenses.
Electro-optical systems enable an optical characteristic to be controlled by means of an electrical stimulus. By way of example, the light transmission of an electrochromic lens varies in response to an electric current.
Electro-optical systems thus require an electrical power supply in order to deliver the electrical stimulus. Small-sized batteries have been integrated with spectacles frames so as to power electro-optical devices integrated with the lenses. Such batteries have been placed on the branches or “temples” of the spectacles, or they have been hidden in the bridge of the frame between the two lenses. Electrical connections then connect the battery(ies) to the electro-optical system.
Such battery power supplies suffer from the drawback of significant weight and size. In addition, they are reserved for lenses that have been specially produced for a frame of given shape. Unfortunately, in most cases, lenses are produced independently of frames. They are then cut, turned, and/or drilled so as to be brought to the dimensions of a frame or a jig, and then they are assembled to the frame or to the jig. Because of the wide variety of shapes of frames and jigs, it is difficult to design electrical connections that include a portion that is made on the lens prior to the lens being cut to size. In addition, such connections need to be connected to the frame after the lenses have been assembled in the frame. Making such connections is particularly expensive since it requires finishing steps to be performed.
An object of the present invention thus consists in proposing an ophthalmic lens fitted with an electro-optical system that does not present the above-mentioned drawbacks.